RADIOACTIVE
by Animaneya
Summary: The world was once a care-free place built on trust and loyalty. But then the Dark Forces arose and brought the world to its knees. All appeared to be lost until four souls were chosen to come together to help defeat the darkness. Can they work together to defeat the darkness or will it consume them first? Based off of the YouTube video. Co-written with starskulls! Please R
1. Chapter 1

Chapter One: Meetings and Greetings

Hiccup blinked open his eyes. He was lying in a misty clearing. Above him the sky was dark and cloudy. There was no sun to be seen, but the land around him was light enough to be considered daytime.

Groaning, he sat up and looked around. Toothless was lying next to him. His eyes were closed and he was letting out little dragon snores, but he seemed ok. _Where are we?_ Hiccup wondered.

The last thing he remembered was taking Toothless out to test a new dive. They were flying over the sea and as they were doing the new dive the sea began to swirl beneath them and the wind picked up.

Toothless had tried to fly away, but the wind pushed them into the water and Hiccup lost consciousness. "Toothless," Hiccup called to his friend. Toothless's eyes shot open and he lifted his head.

"You ok buddy?" Hiccup asked. Toothless nodded his great black head. His whole body was covered in black scales and he had two great black wings that stretched out on either side of him. He had a long tail that ended in two fringes.

One of the fringes was made of the same thing as his wings, the other was a construction Hiccup had made after Toothless had lost half of his tail.

Hiccup struggled to his feet and walked over to Toothless as he also stood up. "We should probably try and find out where we are," Hiccup said. Toothless blinked. "Come on bud," Hiccup crawled into the saddle strapped to Toothless's back.

He fixed his prosthetic foot in the latch on the saddle. When he moved his foot it controlled the fake fringe on Toothless's tail to help him fly. "Ready boy?" Hiccup asked. Toothless flicked his ear and wriggled his hind haunches. Hiccup fixed the fringe then Toothless leapt into the air.

The wind created by Toothless's wings blew away the mist allowing them to see clearly. "There's gotta be a village or something nearby," Hiccup commented as Toothless flew. The wind blew back his dark auburn hair and cooled his face. His green shirt and brown vest whipped around and made flapping noises.

Hiccup glanced down to see the misty clearing had been replaced by a dense forest. The tree branches were tangled and formed a think canopy so that Hiccup couldn't see beneath them. They were bare with leaves scattered here and there on the branches.

"Let's see what's down there boy. There could be people down there and we wouldn't know because of the branches," he patted Toothless's neck. Toothless flew on until there was a slight break and the branches. Tucking his wings in, he lighted down on the ground.

In the forest it was like night. No light penetrated through the thick tangle of trees. Hiccup tore a branch from a tree and put it in front of Toothless's mouth. Toothless lit it with a small blue flame.

A small bubble of light and warmth enveloped them. Their shadows sprang to life and danced on the trees. Hiccup stepped closer to Toothless.

"Let's keep moving," Hiccup suggested. Together they began to push their way through the trees. Toothless's nose twitched, sniffing for anything that might be lurking nearby. Hiccup's eyes darted at the surrounding shadows for any movement. It was a silent walk and both of them were uneasy about it.

The branches over their heads suddenly burst into movement like a great gust of wind had swept through. They froze and looked skyward. Hiccup pulled out the knife he always kept on his belt.

Echoing through the trees came the sound of boyish laughter. Hiccup gasped. He shoved his torch towards the shadows around him to see if anyone was hiding.

"Hmm I wonder who he is," a voice came from above. Startled Hiccup fell backwards against a tree.

"Wh-who's there?" he pointed his knife in front of him. Toothless moved to stand in front of him as a boy appeared in the branches of the tree in front of them. He was pale with frosty white hair and striking blue eyes. He was adorned with a blue hoodie and frayed brown pants. Swung across his shoulders was a wooden staff with a crooked end.

"Can you see me?" the boy asked.

"Yes of course," Hiccup's grip on the knife lessened slightly. "Who are-" he was cut off as Toothless let out a monstrous roar.

The boy looked startled and almost lost his balance on the tree branch. After regaining his composure he swung his staff off his shoulders and pointed the crooked end at Toothless.

"Look out," he shouted as the staff shot out ice and snow. Toothless knocked Hiccup out of the way with his tail and rolled in front of him again. The boy took aim again, but Hiccup jumped in the way.

"No! Don't!" Hiccup yelled. The boy and Toothless both stopped and looked at him. "Don't you dare hurt my dragon," Hiccup said to the boy.

"That's your dragon?" the boy asked.

"Yes, his name is Toothless," Hiccup answered. The boy lowered his staff and a look of confused wonder crossed his face.

"You are certainly an interesting stranger," the boy laughed. He leaned his head against his staff and grinned. He jumped down from the tree and landed in front of Hiccup. "What's your name?"

"I'm Hiccup," Hiccup held out his hand. The boy took his hand. His skin was surprisingly cold and smooth. It sent a shiver up Hiccup's arm.

"I'm Jack Frost."

Rapunzel gasped and shot up from where she was lying on the ground. Surrounding her were dark trees with long twisting branches that reached out to her like grabbing hands. A thick mist weaved its way around her and moved into different shapes in the still air. Rapunzel shivered and pulled her hair closer to her.

Slowly she stood up and looked around for any source of light. The tree branches blocked the view of the world above and closed her in darkness.

"Hello?" she called into the woods. Her voice echoed through the forest. She waited, but there was no reply. "Hello?" she tried again, a little louder this time.

She leaned forward and listened hard for an answer. Again none came, but she did hear something. Far off in the woods came the sound of running water. Hearing the noise reminded Rapunzel of how thirsty she was.

Gathering her very, very, very long blond hair in her arms she headed towards the sound. Her foot bumped something cold and hard. Rapunzel recognized her frying pan. Bending down she picked it up and took it with her.

The mist made it hard to see and several times she almost ran into trees. Her footsteps were agonizingly loud in the dead quiet of the woods. She flinched at every twig that snapped under her bare feet.

As she grew closer to the water it grew louder and she grew thirstier. She began to pick up her pace with every stride. Soon she was running through the gloomy woods. As she broke through the trees and came to the side of a river she stopped running.

Dropping to her hands and knees she crawled to the edge of the river. The water was different from any water she had seen before. It was an odd blue that almost looked grey. Cupping some in her hand she sniffed at it suspiciously. It was warm, but it didn't smell bad. She took a hesitant sip. She waited a moment to see if anything happened.

When she didn't feel any stabbing pains or drop over dead she finished off what was in her hands. Still not feeling any different she drank more and more until her throat stopped burning. Wiping her mouth off with the sleeve of her dress, she sat back and sighed.

"I wonder where I am," she said to herself. The day had started out as any other. She got up at seven and started on her morning routine. After lunch she was staring out the window, waiting for her mother to get back.

"The window," Rapunzel blurted out. "Something happened when I was looking out the window," she said to no one. Racking her brain she struggled to remember what happened. She had been looking at the sky, trying to guess what the clouds looked like as she waited. Then the clouds started to mesh together and swirl around. The swirl got bigger and bigger until it filled up the whole sky. Then the wind picked up and started to pull everything to the swirl, including Rapunzel.

"I guess that swirl brought me here," she mused, glancing around at the creepy place. "Not a very cheerful place." Her eyes traveled upward to the sky. The branches spread out over the river, but they were thinner there and Rapunzel could see the sky.

It was dark and cloudy. A pale moon shone in the sky. Rapunzel felt a flash of comfort at seeing the moon. At least it offered some light. Rapunzel pulled her knees to her chest and hugged them tightly as she gazed at the moon.

As she watched a shadow crept across it. She assumed it was from a passing cloud and thought nothing of it. A twig snapped somewhere in the woods and she glanced away from the moon.

Her heartbeat sped up and she held her breath as her eyes searched the shadows. She clutched her frying pan for protection. When she saw nothing she turned back to the moon.

The shadow had taken the shape of a face in the time Rapunzel had been distracted. It had a wide smile and two empty eyes that stared down at her.

"Ahh," Rapunzel squealed and backed under the trees where she was hidden from the sky. She breathed heavily and wrapped herself in her hair. _I don't like this place at all_, she thought. _I want to go home_.

"Wot was that?" a voice asked from somewhere deeper in the woods. Rapunzel squealed again and pulled her hair closer. "Ther it is again," the voice came again. "Hello?"

"H-hello?" Rapunzel called nervously. Her clutch on the frying pan tightened as a cloaked figure stepped out of the shadows. "Who are you?"

The figure pulled back the cloak to reveal curly red hair and bright blue eyes in a pale round face. It was a girl who looked to be about Rapunzel's age. She was wearing a dark green dress and had a bow over her shoulder with a quiver at her hip.

Following her out of the shadows came a large black horse with shaggy white feet and a white blaze on its face.

"Me name's Merida. This is Angus," she pointed at her horse. "Ooh're you?" she asked. She had a thick accent that Rapunzel had never heard before.

"My name is Rapunzel." Rapunzel shakily rose from her sitting position and lowered her frying pan. Something about this girl gave her the feeling she would not be harmed.

"Nice ter meet ya," Merida extended her hand.

"You too," Rapunzel took her hand and felt immediate relief at being with another person.

**A/N:**

**Hey everyone. So yeah, I started a new story! I'm writing it with my new friend starskulls! Be sure to check out her other stories. This story is based off of the YouTube video by oOZewyOo called RADIOACTIVE. It's really good and you should watch it. Starskulls said she wants eight reviews and some cupcakes so you all better get busy haha. She will be writing the next chapter btw(I wrote this one). Thanks for reading and please review! **

**P.S. This takes place after Brave, HTTYD, and ROTG. Tangled hasn't happened yet. **


	2. Chapter 2

Chapter Two: Jack and Hiccup

"So what are you doing here?" Jack asked brightly but cautiously.  
Hiccup raised an eyebrow," I could ask you the same question Jack" Hiccup said folding his arms, along with Toothless's growl of suspicion.  
Jack shrugged," I was flying one minute, the next thing I know, some wind came up and I was sucked into some swirly looking thing. Not a clue what it was though" Jack replied and Hiccup was shocked at this.  
"You too? That is what happened to me!" Hiccup said in astonishment. Jack ran a hand though his hair in concern.  
"Hmmm… why us though? Why not anyone else? What do you do that other people can't?" Jack asked, looking at Hiccup's appearance and immediately, the Viking frowned as he was offended by this.  
"You just gestured to all of me!" Hiccup said putting his hands on his hips. "I happened to be a Viking!" he said boldly and Jack laughed.  
"Seriously? No offence to you, but you don't seem the Viking type," Jack said and Hiccup rolled his eyes.  
"Yeah, I get that a lot," Hiccup said sheepishly. "No, I am the first dragon conqueror. The place where I live, which is Berk, was once at war with dragons but it all stopped when I met Toothless. I had injured his tail by shooting at him when I was trying to prove myself to my father. I re-built his tail, trained him and eventually, we became best friends. My dad wasn't too happy when he found out," Hiccup said with a grin and Jack was fascinated by this.  
"What did you do when he found out?" he asked, like a child listening to a bedtime story.  
"Well, my dad threw some hurtful words, took Toothless and used him to get to Dragon

Island. There, the big leader of all the dragons came out and attacked all the Vikings that went to the Island. To end the dragon war my friends and I flew in on the dragons that we used for training. You know, preparing us to kill dragons. I managed to rescue Toothless, stop the dragon but lost my foot in the process. Now Berk is at peace with the dragons as they all live among us," Hiccup finished, tapping his metal foot on the ground and Jack seemed amazed by this.  
"That is so cool!" he said with wide eyes, his staff making swirly patterns due to his excitement. Toothless noticed this and he growled at Jack. Hiccup noticed too.  
"Hey what is with that stick thing of yours?" Hiccup asked.  
"It isn't a stick, it's a staff!" Jack scolded, a few flakes falling from the sky at his raised voice.  
Hiccup went behind Toothless's wings at this. There was something about this kid that made him feel unsafe and cautious and Toothless felt the same way.  
"So how did you do that with your staff Jack?" Hiccup asked and Jack twirled his staff in his hand skillfully.  
"I thought my name would give it away! But I take it that you don't get it. I am the spirit of winter, Old Man Winter, Jokul Frosti, you get the idea. I can control ice and snow," Jack explained and Hiccup scoffed.  
"That is just a myth. You're making that up; he isn't really you because he isn't real!" Hiccup said and Jack felt a pang of hurt at this but then he realized something.  
"Really? But if you didn't believe, then you couldn't see me. Besides, how else could my staff do that?" Jack questioned and Hiccup rolled his eyes.  
"Witchcraft! Believe in you? Wow, I thought I was odd!" Hiccup exclaimed, enjoying the look of surprise on Jack's face. Toothless wasn't so easily amused and started to growl but not at Jack. It was like he was sensing something.  
"What is it?" Hiccup asked, feeling a little worried now. Jack said nothing but his eyes seemed to be looking at something behind the Viking. Hiccup, as much as he didn't want to, turned his head around so he could see what Jack was looking at. To his shock and surprise, he saw a black shadow but it wasn't in a shape or form of an animal or a human being but the red eyes stood out from the blackness of the body.  
Hiccup and Jack didn't utter a word but Hiccup was edging over to Toothless and slowly started to climb on his back. The shadow started to move forward and that was when Hiccup started to get up on Toothless much more quickly.  
"Run!" Jack shouted; breaking into a sprint and heading for the trees, with Hiccup and Toothless close behind. The shadow let out a roar and chased after the three with surprising speed. Hiccup looked over his shoulder as did Jack, to see that the shadow was close behind and closing in for the kill.

**A/N:**

**So how did you like this chapter? I thought starskulls did great. Sorry it has taken forever to update, but we are both very busy. Thanks to luv duv-10, bug349, shimmer-snowflake, Floralrma Tylee, hinaharu, and Kasha Eliz for reviewing. You guys are amazing, keep up the good work. Thanks for reading and please review! **


	3. Chapter 3

Chapter Three: Together

"So you got pulled in by some swirly thing too?" Rapunzel checked. Merida nodded, her ginger curls bouncing up and down with the movement.

"I was ridin' Angus and then 'whoosh', I'm her' with ya," she moved her hands as she spoke and gestured around wildly. Rapunzel's eyes widened slightly and she leaned away from her. Merida put her hands down and laughed. "Sorry," Merida apologized. Rapunzel shrugged it off.

"I wonder where here is," she let her eyes travel around the murky woods once more. Merida followed her gaze.

"Wot's that?" she jumped up and pointed her finger into the shadows. Her blue eyes were wide with surprise, not fear. Rapunzel turned around and saw a little green lizard crawling towards them through the dark grass.

"Pascal," she exclaimed. Reaching out she picked him up and placed him on her shoulder. "Don't worry Merida, this is my chameleon Pascal," Rapunzel said. Merida leaned forward and inspected him.

"Wow," she breathed.

"He must have been sucked into the swirl too," Rapunzel said thoughtfully. Merida nodded and sat back down next to the river.

"So wot now?" she asked. Rapunzel shrugged and pulled her hair up around her. Merida eyed her hair. "You got lots a har," Merida commented.

"Yea, uh," Rapunzel stopped talking, she wasn't sure if she should tell Merida about its magical properties. She glanced behind her new friend and saw a shadow slowly moving out of the trees. "Merida," she whispered, her gaze locked on the moving shape.

"Huh?" Merida turned her head to see what Rapunzel was staring at and froze. "Get ter Angus," she whispered. Slowly Rapunzel began to gather her hair to her and stand up at the same time. Merida stood in front of her and pulled her bow from her shoulder.

She fitted an arrow into the string and pulled it back to her cheek. Rapunzel began to inch towards Angus, her eyes never leaving the shadow. Suddenly there was a whoosh of air and the arrow shot into the darkness. "Run," Merida shouted. She swung onto Angus's back then pulled Rapunzel up with her.

As soon as Rapunzel was on Angus took off at a full gallop. His large hooves made dull thumps on the padded ground. Merida knocked another arrow in her bow then shot it back at the shadow that was still moving towards them.

"Faster Angus," she yelled. The shadow was slowly, but surely ganging on them. Merida handed her bow to Rapunzel. "Don't drop it," she snapped. Turning around she grabbed Angus's main and turned sharply around a tree. She made another swerve and still urged him to go faster.

"You're going to hit a tree," Rapunzel gasped as they narrowly avoided a head on collision.

"Quiet," Merida ordered. She glanced back to see that the shadow was beginning to fall back. She made a few more close turns until it was blocked by trees. Smiling she turned back around just in time to see a large black dragon with a boy on its back heading straight towards them.

Rapunzel screamed as Merida yanked Angus to the side, causing him to flip over and make them fall. The dragon reared back and toppled over, dropping the boy to the ground. Another boy appeared with the other one.

He helped the first boy up as Merida pulled Rapunzel to her feet and checked on Angus to make sure he hadn't hurt himself.

"Are you guys ok?" Rapunzel asked the boys.

"Fine," the boy who had been riding the dragon replied. He dusted off his brown vest and green shirt then looked up at them. He had dark auburn hair and olive green eyes with freckles on his cheeks. "You ok Jack?" he looked at his companion.

"Great," the boy grinned. He was slightly taller than the dragon boy and had pale skin with white hair. "How are the girls?" he looked at them.

"I think we're ok," Rapunzel said. The bottom of her dress was slightly ripped, but it was nothing too bad. Merida looked fine too.

"So you can both see me too?" the pale boy asked. Merida gave him an odd look.

"Why? Are some people supposed to be invisible?" Rapunzel asked. It was her first time out of the tower, meeting new people and she wanted to learn everything she could.

"I'm Jack Frost," the boy explained. Rapunzel tipped her head. The boy sighed and shook his head. "You know, spirit of winter, Old Man Winter, Jokul Frosti," he offered. Rapunzel was still confused, but she nodded anyway.

"I'm Hiccup," the dragon boy said. "This is Toothless," he gestured to his dragon. The great black beast sat up and dipped his head.

"I'm Merida, and this is me friend Rapunzel," Merida introduced them. Rapunzel approached the dragon curiously.

"I've never seen a dragon before," she reached out her hand. Toothless sniffed at it. "I've actually never seen so many people before either." They all looked at her. "What?"

"You've never seen more than three people before?" Jack asked. Rapunzel blushed and nodded. Jack opened his mouth to talk again, but before he could speak a terrible noise echoed through the woods. It was like a mix between a scream and a moan and it shoot the ground causing them to fall to their knees.

"What was that?" Jack looked around, his blue eyes wide.

"It's probably that thing that was chasing us," Rapunzel said.

"We were being chased too," Hiccup exclaimed.

"Well it's probably comin' so we outa move," Merida swung onto Angus again. Rapunzel crawled up after her. Hiccup mounted Toothless while Jack rose into the air as if he didn't weight anything.

"How are you doing that?" Rapunzel asked.

"I told you I was Jack Frost," Jack laughed.

**A/N:**

**So here's chapter three. I think this is coming along quite well. You guys are really supportive about it. Thanks to Kasha Eliz, FloralrmaTylee, luv duv-10, bug349, and Orangepaint for reviewing! I just saw the sequel video to the RADIOACTIVE video this is based off of. It's really good, you should check it out. Thanks for reading and please review!**


	4. Chapter 4

Chapter Four: They're Back!

Merida scoffed, "Pah! That nothin' but witchcraft lassie!" she said and Jack was and looked insulted from where he was hovering. Jack glared at her.  
"Witchcraft? Do you see me riding a broom with a pointy hat?" Jack snapped back with a sarcastic tone to his voice. Rapunzel felt a chuckle tickle at her throat as did Hiccup but Merdia wasn't easily amused. More angered than amused.

"Alright pale face, if yer tryin' to be funny, it ain't workin', ya here me?" Merida shot back.

"Really? Then why were the others trying not to laugh?" Jack asked. The pair then started to bicker like two children arguing about who wanted to go down a slide first. Rapunzel shook her head in amusement but then her leaf green eyes widened as she saw two black shadows creeping out from behind some trees. She reached out a hand and waved it at Hiccup but didn't take her eyes off the shadows. Hiccup, who was still watching Merida and Jack fight, didn't notice at first but Toothless did. He gave a growl and turned his head to Rapunzel and then once he did this, Hiccup noticed what Rapunzel was doing.

Hiccup's eyes widened at this and Toothless' bared his teeth and his diamond like pupil's narrowed. "Uh guys?" he said but they still didn't listen. Just the usual, Hiccup thought as he thought of his home.

"What is your problem Frizzy Head?" Jack asked, a little ** off at this girl now. Merida's face was almost as red as her hair now. Frizzy Head?!

"Me?! For all we know, you we're probably the one who brought us here in the first place!" she shouted and Jack glared at her with his icy blue eyes.

"Why would I do that?! I have better things to do than stick around here with you!" Jack snapped back.

"GUYS!" Hiccup shouted, quite annoyed now and this caused the pair to turn their head around at the Viking. They then saw what Hiccup was looking at and their eyes widened.

Rapunzel took in a deep breath, "Nobody move" she said quietly but Merida didn't listen. She slowly reached for an arrow from her quiver and pulled her bow from her back.

Jack saw this and he gritted his teeth. "Frizzy! Don't move!" he hissed but Merida ignored him. She placed the arrow in her bow and pulled it back until it came to her cheek. Rapunzel didn't want to say anything as Merida was the first actual person she had made a friend in 18 years and didn't want to argue with her. Hiccup didn't want to argue either as Merida looked quite tough and wasn't someone to be messed with but Jack didn't care about this at all.

"Merida!" Jack hissed, louder this time but Merida still didn't listen. As the shadows came closer, they formed into wolves with piercing red eyes. They had very sharp teeth and had paws with razor sharp claws. Merida then let go of the arrow and it shot one of the wolves in the head. Merida smiled in victory but then her smile faded as the wolf did nothing but shake his head so the arrow was flicked out of his head. This seemed to aggravate them and thick drool spilled out of their mouths and they started to growl for their kill.

"Oh you shouldn't have done that" Hiccup said with a little nervousness in voice, and then tapped Toothless on the head so he started to back away. Merida slowly put her bow back where it belonged and she pulled the reins on Angus so he started to back away too. Jack started to hover back too and he was then next to speak.

"Guys, run and I will hold them off" Jack whispered and Rapunzel stared at him in horror.

"No way! They will rip you to shreds!" she protested.

Hiccup looked up at Jack, "She's right!"

Merida rolled her eyes; what was he trying to do, be a hero? "They're right Snowflake, ya can't fight them all yerself. If we're gonna do anythin', we're gonna run outta this together" she said, acting like a leader.

Jack sighed as he saw that they were serious, so he put on his serious face which he didn't do very often. He then said six words that then caused shivers to go down everybody's spines. "You have to believe in me."

**A/N: **

**Here's chapter four! Starskulls wrote this so everyone congratulate her on her wonderful job. Hmmm I don't really know what to write… Oh! I'm finishing Driver's Ed this week and then I'm gonna be camping this weekend so I don't know when I'll get the next chapter up :/ I'll try to get it up soon, but no promises. Thanks to AdmiringRoseBlossom11, HeyDickGrayson, bug349, hiddensecret564, Kasha Eliz, FloralrmaTylee, and luv dove-10 for reviewing. Thanks for reading and please review! **

**P.S. for all of you reading my fic Making Magic we get to find out who Jack's father is in the next chapter. Any guesses? **


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